USB2 expansion card causes conflict on dual G5

Lt Major Burns

"Dicky" Charlteston-Burns
as the flagship apple mac has only 3 usb slots, i quickly ran out. i installed a no-brand, dabs value usb2 expansion, with 4 external and 1 internal usb2 slots. no software was needed, they all started working perfectly.

within a few weeks, i notcied my shuffle wasn't charging in the front usb slot where it usually lives. it transferred ok, but didn't charge at all... strange.

i then started getting "[blah] is draining too much power from the usb slot. stopping this slot now" and it would kill the first usb slot in my keyboard until next login. that's 2 not working properly.

then my keyboard stopped working. it said it was looking for bluetooth keyboard. (i don't have one, the usb keybard was plugged into the back of my display.) it was then, i realised my display usb wasn't working. but sometimes does. i put this all down to a fault in the usb at the back where the display was plugged in. but then the shuffle worked fine in that.

at this point i have nearly everything plugged into the usb2 card, looking like a dirty pc, as it was the only thing left that worked.

i ran the apple hardware test, having ripped it out cos it told me to. it passed, no issues.

i havent put it back in and now everything works. except i have 4 less usb slots, that i really do need (mouse, shuffle, usb key, keyboard, scanner, printer, usb2 external harddrive, display, camera)

why did this cause a conflict?


wow, 1.4g is way faster!
you got me. what do apple techs say at the store? the only thing that i can think of is that the pci bus isn't providing enouph power to the card and therefore to the usb ports. i got a da g4 with a sonnet tempo trio and a no name usb2 card and all the ports full with no problems. the only difference is that i'm not trying to charge a shuffle. i would try useing a powered hub on the card then plug the suffle into it, and everything back in the g5 with the card installed.


U.S.D.A. Prime
What voltage does that PCI card run ("signal") at?

While earlier Macintosh computers, like the G4 and G3 could take cards at either 3.3v, 5.0v or 12v, the G5 machines require that you use 3.3v signalling cards. Placing a card in there that doesn't use 3.3v signalling can damage the machine.

It could also be just a general incompatibility. You did say that the PCI card was a "value-branded" card, and lower-end cards tend to be less forgiving of the situations they're used in.